Massive Thrombosis of the Coronary Sinus As an Unusual Complication of Transvenous Pacemaker Insertion in a Patient with Persistent Left, and No Right Superior Vena Cava

Persistent left superior vena cava associated with lack of a right superior vena cava constitutes a rare anomalous pathway of venous return to the heart; drainage is usually into the coronary sinus. The patients often are asymptomatic and the anomaly is detected only accidentally during catheterization of the right heart. The patient reported here (an 85‐year‐old man) had the foregoing abnormal form of venous return, which presented great difficulty when insertion of a transvenous pacemaker was attempted. Subsequently the patient died from bronchopneumonia, and postmortem examination revealed massive thrombosis of the coronary sinus. This may be the first report of such a complication of intravenous pacemaker implantation. Complete occlusion of the coronary sinus in this situation may prevent venous return from the upper part of the body. The literature is reviewed and recommendations are made for alternative management of this unusual problem.